Rebecca Yarros’ Empyrean Series centers around Basgiath War College, the fictional military academy located in the kingdom of Navarre. The school is located in the center of the Morraine Province, and is in close proximity to the dragon hatching grounds—also known as the vale. Basgiath’s cadets are split into four Quadrants, with candidates choosing to enter into the Infantry, Scribe, Healer, or Riders Quadrant. Each Quadrant seen in the Empyrean Series books are of equal importance to the protection of Navarre, but there’s a definite hierarchy when it comes to skills acquired.

https://screenrant.com/fourth-wing-every-quadrant-basgiath-war-college-explained/